Current state of the art includes many systems designed for generation of hydrogen. Systems developed for this purpose have many adverse effects, including use of chemicals that can cause significant risks for human health and environment, large power requirements, the inability to utilise the materials as efficiently as desired, the inability to utilise the catalysers in an efficient way, the large volumes of space required for these systems, and the fact that solid wastes in the system block the product output ports. It is known that materials like hollow fibre with selective permeability properties are also used in these systems. However, the systems in the current state of art frequently face problems like accumulations in the system due to failure to properly secure the hollow fibres, the hollow fibres not being able to maintain their integrity, the inability to clean hollow fibre surfaces, and the unsecured hollow fibres blocking flow paths and preventing flow and thus decreasing efficiency.
The literature includes patents for systems wherein hydrogen gas is generated by various methods, including generation of hydrogen gas from chemical hydrides. These systems require extra energy for driving the cylinders and production of these cylinders is a costly process. It is generally unlikely to be able to reuse the system components, and both input materials and final products come with storage problems.
The United States of America patent document numbered U.S. Pat. No. 7,858,068, an application in the state of the art, discloses a chemical reaction consisting of a process of small tablets comprised of catalyser or solid acid on the outside and chemical hydrides on the inside being placed in a tank filled with water. The acid dissolving in the water acts as a catalyser, reacting with the chemical hydrides dissolving in the water, and the hydrogen gas generated in result of this reaction is collected. However, use of strong acids in such applications constitute a serious hazard for human health and environment in case of a potential leak or rupture. In this system, initiation of the reaction is completely left to happen on its own. However, since it is not possible to implement a continuous operation in this system, it causes loss of time and fails to provide an efficient solution.
The United States of America patent document numbered U.S. Pat. No. 4,155,712, an application in the state of the art, discloses a system for gathering hydrogen gas generated by means of evaporating the water in a tank, forcing this vapour through a hydrofobic membrane only allowing passage of water vapour, causing the water vapour to enter chemical reaction with chemical hydrides it is passing over, thus generating hydrogen gas. Since no catalyser is used in this system the reaction takes place very slowly and only a small amount of hydrogen gas is generated. The fact that the system can only meet simple and small energy needs while requiring a very large volume of space demonstrates that it will have a very low efficiency.
The United States of America patent document numbered US20050058595, an application in the state of the art, discloses a process involving passing a chemical hydride solution through a tank filled with hollow fibre structures and generates hydrogen on the outer surface of hollow fibres which are coated with the catalyser. The generated hydrogen passes through the channels with small pores to the side surfaces of the tank which only allow passage of hydrogen gas, and fills it into a second tank. Here, the solid waste created when the reaction of solution passing through the densely packed hollow fibres will accumulate and obstruct the flow in the system. In case of long term use the hollow fibres will not be able to maintain their structure and location due to gravity effects and become inoperable due to eventual distortions and ruptures.
The United States of America patent document numbered U.S. Pat. No. 6,409,976, an application in the state of the art, discloses a system using a porous structure coated with catalyser on the inside. The prepared solution is passed through the hollow fibres placed inside this structure. The hydrogen gas generated by the reaction taking place inside this structure passes through channel to leave the system and it is stored in a separate place. Accumulation of solid wastes generated by the reaction on the porous structure both covers the catalyser coated surfaces and blocks flow paths, necessitating continuous maintenance and cleaning, which is a costly process.
The United States of America patent document numbered US20060269470, an application in the state of the art, discloses a method for generating hydrogen gas by means of a reaction between a sodium borohydride compound sent into a reaction tank in solid form, and an acid solution pumped into the same reaction tank. The hydrogen gas generated in result of the reaction is sent to a fuel cell by means of a hydrogen separator apparatus. The generated hydrogen gas and the oxygen in the air react inside the fuel cell to generate water, which is optionally sent to the acid tank or reaction tank for dilution. The said system carries some problems like the inability to control concentration of the utilised acid, the need for additional lead time for initial dilution, the difficulty of reusing and storing the acid, and the fact that the said acid is hazardous for human health and environment.
The United States of America patent document numbered US20040258966, an application in the state of the art, discloses three different designs for generating hydrogen gas by using a sodium borohydride solution. The first design involves a reaction which generates hydrogen gas by passing polymer films, carrying sodium borohydride solution in the cells on them, through two cylinders coated with the catalyser. In another embodiment polymer film surface is coated with the catalyser and the micro-globe structures containing sodium borohydride are found on the film. When the polymer film passes through the cylinders the micro-globe structures are crushed, contact the catalyser surface and enter reaction to generate hydrogen gas. In another embodiment sodium borohydride compound is found on the polymer film in solid form, and the polymer film is passed through hollow fibres coated with catalyser on the outside. Coating of the surface of hollow structure can obstruct passage of water due to the risk of losing porosity, and in result the reaction between water and sodium borohydride particles may not take place.
The United States of America patent document numbered US2012067211, an application in the state of the art, discloses a porous hollow fibre structure treated with a hydrogen permeable palladium or palladium alloy layer. The said hollow fibre has an inner diameter of 30 to 1500 microns and an outer diameter of 100 to 2000 microns. These structural properties create a large surface area and allow efficient separation of hydrogen. Processing and material costs are high, since the building material for hollow fibres is stainless steel. In addition, it also has disadvantages in regard of weight and volume. Hydrogen is generated by burning CH4 and CO, and CO2 is generated as a waste product. Therefore, this also isn't an environmentally-friendly solution.
The Japan patent document numbered JP2000044201, an application in the state of the art, discloses a hydrogen generation tank wherein hydrogen productivity is increased. Inside the said tank catalyser is brought into contact with the hydride containing liquid mixture by means of a rotary propeller. The structure of the said propeller is designed to ensure efficient reaction between the catalyser and the mixture. It is stated that the propeller plates may have foils and holes on them. The catalyser is added into the mixture and there is possibility for the catalyser to precipitate at the bottom, which would decrease the contact surface between the catalyser and the liquid mixture. In addition to the mixing motor, the system also requires a power consuming light source for the reaction to take place.
The Japan patent document numbered JPS58145601, an application in the state of the art, discloses a low cost metal hydride reactor providing high hydrogen yield. The reactor in question contains a porous cylindrical unit and multiple plates reaching from this unit to reactor walls, increasing the rate of generation of hydrogen from hydrides by increasing the surface area. It is stated the cylindrical structure is made of aluminium which allows passage of hydrogen but prevents passage of metal hydride. Since the cartridge is made of mostly aluminium material, the system has a heavier structure in comparison to those using polymeric materials. In addition, the system in the said application is used to both generate and store the hydrogen gas, wherein the gathered hydrogen gas will slow down reaction speed and cause the efficiency to decrease in time.
The United States of America patent document numbered U.S. Pat. No. 7,947,096, an application in the state of the art, discloses a hydrogen generator wherein the water is separately fed into the reactor. The said process involves one water intake and one hydrogen output channel. Hydrogen gas is generated by metals inside the reactor coming into contact and reacting with the water. It is mentioned that hydrides are stored in a separate tank and transferred from there to the reactor, wherein the reaction is supported by a catalyser and permeability is provided by means of a porous core structure. It is pointed out that metal hydride can also be used in powder form in order to increase the reaction surface. The fact that cartridge structures are depleted in time and have to be replaced creates an ongoing extra cost. Since the cartridge is made of mostly aluminium material, the system has a heavier structure in comparison to those using polymeric materials.